CN115831819A - A self-cleaning method for etching equipment - Google Patents

Abstract

The application discloses a self-cleaning method for etching equipment, which relates to the field of semiconductor manufacturing. The method includes: periodically pumping the reaction chamber of the equipment daily, including: S1: controlling the air pressure in the reaction chamber of the equipment to alternate between the first high pressure and the first low pressure; Introduce the first cleaning gas; when the VAT is fully open, inject the second cleaning gas; S2: adjust the RF power of the electrodes in the reaction chamber of the equipment to the first power, adjust the air pressure to the second high pressure, and simultaneously inject the third cleaning gas, That is, NF ₃ gas; S3: adjust the air pressure in the reaction chamber of the equipment to the second low pressure, and at the same time introduce the fourth clean gas, that is, the mixed gas of NF ₃ and O2; S4: control the air pressure in the reaction chamber of the equipment at the third high pressure and the third low pressure alternately; and feed oxygen with the first high flow rate during high pressure; feed oxygen with the first low flow rate during low pressure. Through the above method, the problem of block etching defects formed on the surface of the wafer is solved.

Description

A self-cleaning method for etching equipment

technical field

This application relates to the field of semiconductor manufacturing, in particular to a self-cleaning method for etching equipment.

Background technique

Shallow trench isolation etching and polysilicon gate etching are key processes for defining the size of semiconductor devices, so the requirements for etching equipment are also very strict.

Usually, for the equipment reaction chamber in the etching equipment, a WAC (waferless auto clean, wafer-free automatic dry etching cleaning) is performed every time a wafer is processed to clean the equipment reaction chamber. However, due to the mixed operation of multiple processes in etching equipment, different by-products are mixed, and the formed mixture may fall on the gas nozzle pipe in the reaction chamber of the equipment, the valve body and valve plate of the molecular pump and other positions. These locations are difficult for WAC to clean, resulting in by-product buildup.

Before or during the etching of the wafer in the reaction chamber of the equipment, under the action of gas and charge, the by-products may fall on the Wafer surface, resulting in blocky etching defects on the wafer surface, which will affect the product. Yield has a big impact.

Contents of the invention

In order to solve the problems in related technologies, the present application provides a self-cleaning method for etching equipment. The technical solution is as follows:

A self-cleaning method for etching equipment, the method is applied to the etching equipment, the equipment reaction chamber of the etching equipment is provided with an air inlet unit, an air outlet channel and a device for controlling whether the air outlet channel is conducted or not. VAT, when the VAT is fully open, the air outlet channel is conducted, and when the VAT is fully closed, the air outlet channel is not conducted; it is characterized in that the method includes:

According to the preset cleaning cycle, perform daily pumping treatment on the reaction chamber of the equipment;

The daily pumping treatment includes:

S1: By controlling the switch of the VAT, the air pressure in the reaction chamber of the equipment is alternately between the first high pressure and the first low pressure; The first cleaning gas, so that the air pressure is the first high pressure; when the VAT is fully opened, the second cleaning gas is introduced into the reaction chamber of the equipment through the air intake unit, so that the air pressure is the first low pressure;

S2: Adjust the radio frequency power of the electrodes in the reaction chamber of the device to the first power, and at the same time pass the third clean gas into the reaction chamber of the device through the air intake unit, so that the air pressure is adjusted to a second high pressure; wherein, the The third cleaning gas is NF ₃ gas;

S3: Introduce the fourth cleaning gas into the reaction chamber of the equipment through the air intake unit, and adjust the air pressure in the reaction chamber of the equipment to a second low pressure, wherein the fourth cleaning gas is NF ₃ and O ₂ mixed gas;

S4: By controlling the switch of the VAT, the air pressure in the reaction chamber of the device is alternately between the third high pressure and the third low pressure; Oxygen, so that the air pressure in the reaction chamber of the device is adjusted to a third high pressure; when the VAT is fully open, oxygen is introduced through the air intake unit at the first low flow rate, so that the air pressure in the reaction chamber of the device is adjusted to the third low pressure.

Optionally, after the S4, it also includes:

S5: performing WAC treatment on the reaction chamber of the device to form a layer of SiO ₂ on the inner wall of the reaction chamber of the device.

Optionally, the types and contents of the first cleaning gas and the second cleaning gas are different.

Optionally, in the S1, the first high pressure is 400-500mT, the first low pressure is 0-50mT, and a single duration of the first high pressure and the first low pressure is 10s.

Optionally, in the S2, the first power is 1000-1500W, and the second high voltage is 200-300mT.

Optionally, in the S3, the second low pressure is 0-20mT, and the flow rate of the fourth cleaning gas is less than 250 sccm.

Optionally, in the S4, the third high pressure is 400-50mT, the third low pressure is 0-50mT, and the single duration of the third high pressure and the third low pressure is 10s.

Optionally, in said S4, the first high flow rate is 300-550 sccm, and the first low flow rate is less than 50 sccm.

Optionally, the air intake unit is a gas injection device.

The technical solution of the present application at least includes the following advantages:

1. First, through the execution of S1, the loose by-products in the VAT and equipment reaction chamber can be blown away; after that, through the execution of S2, the inner wall of the equipment reaction chamber and the LRS window can be cleaned; through the execution of S3, the Clean the air intake unit, such as the nozzle of the gas injection equipment; through the execution of S4, the organic polymer-based by-products remaining in the reaction chamber wall of the equipment and the air intake unit can be cleaned. In short, through the above method Execution, can effectively remove by-products remaining in the equipment reaction chamber, air intake unit and VAT, and solve the problem of by-products falling to the wafer surface during the etching process and eventually forming blocky etching defects;

2. After cleaning, perform WAC treatment on the equipment reaction chamber to form a layer of SiO ₂ on the inner wall of the equipment reaction chamber, which helps to ensure that the environment of each wafer in the equipment reaction chamber is consistent and stable.

Description of drawings

In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the specific embodiments or prior art. Obviously, the accompanying drawings in the following description The drawings are some implementations of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

Fig. 1 is a schematic structural diagram of a reaction chamber of a device provided by an embodiment of the present application;

FIG. 2 is a schematic flowchart of a daily pumping process in a self-cleaning method for etching equipment provided by an embodiment of the present application.

Explanation of reference signs: 1. Equipment reaction chamber; 11. Air intake unit; 12. VAT.

Detailed ways

The technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, use a specific orientation construction and operation, therefore should not be construed as limiting the application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connection, or integral connection; it may be mechanical connection or electrical connection; it may be direct connection or indirect connection through an intermediary, or it may be the internal communication of two components, which may be wireless connection or wired connection connect. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

In addition, the technical features involved in the different embodiments of the present application described below may be combined as long as they do not constitute a conflict with each other.

Please refer to FIG. 1 , which shows a schematic structural diagram of a reaction chamber of a device provided by an embodiment of the present application. The upper part of the reaction chamber 1 of the device is provided with an air intake unit 11 , such as a gas injection device, to feed gas into the reaction chamber 1 of the device. The bottom of the reaction chamber 1 of the equipment is provided with an air outlet channel and a VAT (swing valve) 12. By controlling VAT12, it is possible to control the conduction of the air outlet channel, and when the VAT12 is fully open, the air outlet channel is conducted. The air outlet channel is not conducting.

The embodiment of the present application also discloses a self-cleaning method for etching equipment, the method at least includes the following steps:

According to the preset cleaning cycle, the reaction chamber of the equipment is pumped daily.

Exemplarily, the reaction chamber of the equipment can be pumped daily with a once-a-day cleaning cycle.

Referring to Fig. 2, the above-mentioned daily pumping process includes at least the following steps:

S1: By controlling the switch of the VAT, the air pressure in the reaction chamber of the equipment is alternately between the first high pressure and the first low pressure; when the VAT is fully closed, the first clean gas is introduced into the reaction chamber of the equipment through the air intake unit, and The air pressure is the first high pressure; when the VAT is fully open, the second clean gas is introduced into the reaction chamber of the equipment through the air intake unit, and the air pressure is the first low pressure.

Exemplarily, the staff can first control the VAT to be fully closed and last for 10s. During this process, the first cleaning gas is introduced into the reaction chamber of the equipment through the air intake unit, and the air pressure in the reaction chamber of the equipment Adjust to first high pressure. After the fixed duration is over, set the VAT to the fully open state. During this process, the second clean gas is introduced into the reaction chamber of the equipment through the air intake unit, so that the air pressure in the reaction chamber of the equipment is adjusted to the first Low pressure until the fixed duration elapses. Through the multiple switching of the above two modes, the VAT and loose by-products in the reaction chamber of the equipment can be blown away.

Further, in some embodiments, the types and contents of the first cleaning gas and the second cleaning gas mentioned above are different.

Further, in some embodiments, the above-mentioned first high pressure is 400-500mT, the first low pressure is 0-50mT, and the fixed duration of the first high pressure and the first low pressure may be 10s.

S2: Adjust the RF power of the electrodes in the reaction chamber of the equipment to the first power, and at the same time pass the third clean gas into the reaction chamber of the equipment through the air intake unit, so that the air pressure is adjusted to the second high pressure, wherein the third clean gas is NF ₃ gas.

Exemplarily, after S1 is completed, the second cleaning gas in the reaction chamber of the device is completely removed. After that, the staff can adjust the RF power of the electrodes in the reaction chamber to the first power, and adjust the VAT to a fully closed state, and at the same time, pass the third clean gas into the reaction chamber of the equipment through the air intake unit, so that the air pressure is adjusted to second high voltage. Wherein, the third cleaning gas is NF ₃ gas, so that the inner wall of the equipment reaction chamber and the LRS window can be cleaned.

Further, in some embodiments, the above-mentioned first power may be 1000-1500W, and the second high voltage may be 200-300mT.

S3: Introduce the fourth cleaning gas into the reaction chamber of the equipment through the air inlet unit, and adjust the air pressure in the reaction chamber of the equipment to the second low pressure, wherein the fourth cleaning gas is a mixed gas of NF ₃ and O ₂ .

Exemplarily, after the third cleaning gas is completely discharged, the VAT can be adjusted to a fully open state, and the fourth cleaning gas is introduced into the reaction chamber of the equipment through the air intake unit, and the air pressure in the reaction chamber of the equipment is adjusted to the first Second, low pressure, wherein the fourth cleaning gas is a mixed gas of NF ₃ and O ₂ , so that the air intake unit, such as the nozzle of the gas injection device, can be cleaned.

Further, in some embodiments, the above-mentioned second low pressure is 0-20 mT, and the flow rate of the fourth cleaning gas is less than 250 sccm.

S4: By controlling the switch of the VAT, the air pressure in the reaction chamber of the equipment is alternately between the third high pressure and the third low pressure; The air pressure in the reaction chamber is adjusted to the third high pressure; when the VAT is fully open, oxygen is fed through the air intake unit at the first low flow rate, so that the air pressure in the reaction chamber of the equipment is adjusted to the third low pressure.

Exemplarily, the staff can first control the VAT to be fully closed and last for 10s. During this process, oxygen is introduced into the reaction chamber of the equipment through the air intake unit at the first high flow rate, and the reaction chamber of the equipment The air pressure is adjusted to the third high pressure. After the fixed duration is over, set the VAT to a fully open state. During this process, oxygen is introduced into the reaction chamber of the equipment through the first low flow rate of the air intake unit, so that the air pressure in the reaction chamber of the equipment is adjusted to Third low pressure until the end of the fixed duration.

Further, in some embodiments, the above-mentioned third high pressure is 400-50mT, the third low pressure is 0-50mT, and the single duration of the third high pressure and the third low pressure is 10s.

Further, in some embodiments, the above-mentioned first high flow rate is 300-550 sccm, and the first low flow rate is less than 50 sccm.

Further, in some embodiments, after the above S4, the following processing is also included:

S5: WAC treatment is performed on the reaction chamber of the device to form a layer of SiO ₂ on the inner wall of the reaction chamber of the device.

Exemplarily, by performing conventional WAC treatment on the equipment reaction chamber, a layer of SiO2 that is not easy to fall can be formed on the inner wall of the equipment reaction chamber, so as to ensure that the environment of each wafer in the equipment reaction chamber is consistent and stable.

To sum up, the self-cleaning method for etching equipment provided in the embodiment of the present application is to blow away VAT and relatively loose by-products in the equipment reaction chamber through daily pumping of the equipment cleaning chamber and through the execution of S1; After that, through the execution of S2, clean the inner wall of the equipment reaction chamber and the LRS window; then through the execution of S3, clean the air intake unit, such as the nozzle of the gas injection equipment; finally, through the execution of S4, clean the inner wall of the equipment reaction chamber Cleaning with organic polymer-based by-products remaining in the air intake unit can finally effectively remove the residual by-products in the equipment reaction chamber, air intake unit and VAT, and solve the problem of by-products falling to the crystal during the etching process. Round surfaces, eventually forming a problem with blocky etch defects.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or changes derived therefrom are still within the protection scope of the invention of the present application.

Claims (9)

1. A self-cleaning method of etching equipment is applied to the etching equipment, an equipment reaction cavity of the etching equipment is internally provided with an air inlet unit, an air outlet channel and a VAT (vacuum valve actuation) for controlling the conduction of the air outlet channel, when the VAT is fully opened, the air outlet channel is conducted, and when the VAT is fully closed, the air outlet channel is not conducted; characterized in that the method comprises:

performing daily pumping treatment on the equipment reaction cavity according to a preset cleaning period;

the daily pumping treatment comprises the following steps:

s1: alternating the gas pressure in the reaction chamber of the device between a first high pressure and a first low pressure by controlling the switching of the VAT; when the VAT is completely closed, introducing first cleaning gas into the equipment reaction cavity through the gas inlet unit, so that the gas pressure is first high pressure; when the VAT is fully opened, introducing second clean gas into the equipment reaction cavity through the gas inlet unit, so that the gas pressure is first low pressure;

s2: adjusting the radio frequency power of the electrode in the equipment reaction cavity to be first power, and simultaneously introducing third cleaning gas into the equipment reaction cavity through the gas inlet unit to adjust the gas pressure to be second high pressure; wherein the third cleaning gas is NF ₃ A gas;

s3: introducing fourth cleaning gas into the equipment reaction cavity through the gas inlet unit, and adjusting the gas pressure in the equipment reaction cavity to a second low pressure, wherein the fourth cleaning gas is NF ₃ And O ₂ The mixed gas of (1);

s4: alternating the gas pressure in the reaction chamber of the device between a third high pressure and a third low pressure by controlling the switching of the VAT; when the VAT is fully closed, introducing oxygen at a first high flow rate through the air inlet unit, so that the air pressure in the equipment reaction cavity is adjusted to a third high pressure; when the VAT is fully opened, oxygen is introduced through the air inlet unit at a first low flow rate, so that the air pressure in the reaction cavity of the equipment is adjusted to a third low pressure.

2. The method of claim 1, further comprising, after the S4:

s5: performing WAC treatment on the equipment reaction cavity to form a layer of SiO on the inner wall of the equipment reaction cavity ₂ 。

3. The method of claim 1, wherein the first cleaning gas and the second cleaning gas are different in type and content.

4. The method according to claim 1, wherein in S1, the first high pressure is 400-500mT, the first low pressure is 0-50mT, and the single duration of the first high pressure and the first low pressure is 10S.

5. The method of claim 1, wherein in S2, the first power is 1000-1500W and the second high voltage is 200-300mT.

6. The method as claimed in claim 1, wherein the second low pressure is 0-20mT and the fourth cleaning gas is introduced at a flow rate of less than 250 seem in S3.

7. The method of claim 1, wherein in S4, the third high pressure is 400-50mT, the third low pressure is 0-50mT, and the single duration of the third high pressure and the third low pressure is 10S.

8. The method as claimed in claim 7, wherein in the step S4, the first high flow rate is 300-550 seem, and the first low flow rate is less than 50 seem.

9. The method of claim 1, wherein the gas inlet unit is a gas injection device.

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